This image shows the density of observed objects in the third XMM-Newton Serendipitous Source Catalog (3XMM-DR4), mapped in galactic coordinates. The inset shows an expanded view of the small region indicated where the individual sources can be seen. // ESA/XMM-Newton/EPIC/M. Watson (University of Leicester)

Scientists led by the University of Leicester in the United Kingdom have set a new record for cosmic X-ray sources ever sighted, creating an unprecedented cosmic X-ray catalog that will provide a valuable resource, allowing astronomers to explore the extreme universe.

The XMM-Newton Survey Science Center, led by a team from the University of Leicester’s Department of Physics and Astronomy, used the university’s “ALICE” supercomputer to help them produce a new X-ray catalog, dubbed “3XMM.”

This new catalog contains over half a million X-ray source detections, representing a 50 percent increase over previous catalogs, and it is the largest catalog of X-ray sources ever produced. This vast inventory is also home to some of the rarest and most extreme phenomena in the universe, such as tidal disruption events — a black hole swallows another star, producing prodigious outbursts of X-ray emission.

“The catalog contains more than half a million sources, all of which are provided to a better quality than ever before,” said Mike Watson of the University of Leicester. “Using the University’s £2.2m [$3.4 million] High Performance Computer meant we could process the data up to a hundred times faster than before. This was key for testing and implementing advanced new processing strategies. The catalog provides enormous scope for new discoveries as well as in-depth studies of large samples. XMM-Newton is pre-eminent among current X-ray missions in its ability to perform ‘survey’ science with a chance to find previously undetected objects and then explore their properties.”

The catalog provides an exceptional data set for generating large well-defined samples of objects, such as active galactic nuclei, clusters of galaxies, interacting compact binaries, and active stellar coronae.

The XMM-Newton Survey Science Center is one of the teams behind the European Space Agency’s (ESA) X-ray Multi-Mirror Mission (XMM-Newton). Since Earth’s atmosphere blocks out all X-rays, only a telescope in space can detect and study celestial X-ray sources. The XMM-Newton mission is helping scientists solve a number of cosmic mysteries, ranging from the enigmatic black holes to the origins of the universe itself.

The sources in the 3XMM catalog are identified and isolated from serendipitous data recorded by XMM-Newton’s EPIC X-ray cameras, which was built by a team also led by the university. In each of the 600–700 observations made each year, around 70 extra sources are captured in addition to the target object, which usually only takes up a small fraction of the field of view. Covering observations between February 2000 and December 2012, the catalog contains some 531,261 X-ray source detections relating to 372,728 unique X-ray sources.

“The third XMM-Newton Serendipitous Source Catalog shows how much added value can be gained from the observations,” said Watson. “I’d like to pay tribute to the efforts of the whole team, which were crucial to completing this major undertaking.

“3XMM is the largest catalog of X-ray sources ever produced. As such, it offers an unparalleled resource for exploring cosmic X-ray populations, in particular in studying active galactic nuclei (AGN) — those galaxies such as quasars, which harbor a supermassive black hole at their centers. Such active galaxies dominate the detections in the 3XMM catalog, meaning that 3XMM is the key to unlocking a storehouse of several hundred thousand AGN.”